Justin Timberlake and Jimmy Fallon really put house band The Roots to work last night as the pair tackled bits and bobs of hip-hop pop history.

The former was on Fallon's "Late Night" on NBC to promote "The Social Network," but we all know it was ample opportunity for both personalities to do some impressions -- of rappers from Sugarhill Gang and Digital Underground's Humpty Hump to Dre and Snoop Dogg, Missy Elliott to Soulja Boy to T.I. and then, naturally, shining the bit off with Jay-Z's "Empire State of Mind."

Timberlake may be taking a break from working on his music and -- largely -- the music of others to do this whole "acting" thing, but the breathlessness of this clip is a keen reminder: JT, we miss you and we want you back making future-sex-love-sounds. Fallon, who is not normally to my taste, actually managed to keep up, too.

"The thing that makes our show kind of different is that we embrace hip-hop. ... We're that generation where hip-hop is what we grew on," Fallon told the AP. "Everyone's so smiley and running around the office like very confident today, because everyone sees the blogs and gets the e-mails. It just puts everyone in a great mood."

What do you think of the bit? Who did they leave out?

[Video after the jump...]